A Study On Source-grid-load Interaction In Active Distribution Network

With the growing problems such as energy shortages and pollution, as well as the increasing user demand for electricity, traditional power system has been showing a lot of deficiencies. In this situation, a variety of distributed power is getting an greater share in power system because of its cleanliness, efficiency, low-cost, renewability and so on.Among these new distributed power, wind power and photovoltaic power accounts for a large proportion. However, one of the most important character of distributed generation is that it is very random, unpredictable and may affect the security and stability of the grid, for which new requirements of power system must be met. And this is where the concept of ‘source-grid-load interaction’ comes from. The existing research of grid interaction does not consider the problem as a whole. Rather, it only aims at one partial aspect, for instance, source-grid interaction or user interaction. Moreover, former researchers haven’t set an accurate and comprehensive index system to evaluate the level of interaction. In terms of the establishment and solving of mathematical models, the previous algorithm is also considered not comprehensive. The problem cannot be simplified as a unit commitment problem, only considering energy consumption without source-grid-load interaction.To start with, this paper tries to explain the concept of source-grid-load interaction.It then gives an analysis of the characteristics of flexible grid on each side and a variety of interactive mode. On this basis, the overall connotation of source-grid-load interaction is given, including the internal mechanism, and the means of achieving and the fundamental principles, etc. Under this framework, an index system of multi-objective source-grid-load interaction of active distribution networks is proposed, including that of the supply side, the grid side and load side, as well as the interactive level index. Basedon that, a global index system is generated.To move on, the internal mechanism of source-grid-load interaction in active distribution network is studied, by establishing and analying a mathematical model of distributed generators, along with network and flexible load. When solving the model, it is required that some improvements be made in existing optimization objective function.Last, a PSO algorithm is applied for solving a specific numerical example, to get the realization mechanism of the whole problem.